/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Remesher.h
After we split an edge, we have created a new edge and a new vertex. The edge needs to inherit the constraint on the other pre-existing edge that we kept. In addition, if the edge vertices were both constrained, then we /might/ want to also constrain this new vertex, possibly project to constraint target.
virtual void UpdateAfterSplit ( int edgeID, int va, int vb, const [FDynamicMesh3::FEdgeSplitInfo](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3\FEdgeSplitInfo) & splitInfo )